Audiphone



Dec. 8 1925.

DE ELBERT A. REYNOLDS AUDI PHONE Filed June 17. 1918 v, E WM I 11 ven 'tpr:

Patented Dec. 8, 1925.

PORATION OF DELA'WARE.

Application filed June 17, 1918.

To all whom it may concern:

Be it known that I, DE Emsnn'r A. REYN- OLDS, a citizen of the United States of America, residing at Veehawken, county of Hudson, State of New Jersey, have invented certain new and useful Improvements in Audiphones, of which the following is a specification.

My present invention has special reference to telephone apparatus designed to gather and electrically transmit vibrations or soundwaves emitted some distance from the apparatus, on the principle of the audiphone, with provisions for electrical transmission, and essentially embraces a sensitive transmitter with means for gathering such sound waves and conveying them to such transmitter. This has heretofore been attempted through the use of a large mouth-piece or horn, the sound waves or vibrations striking the transmitter or horn in substantially a straight line and conveying to the instrument all jars and echoes attendant such sound waves.

Such a form of construction is open to serious criticism in telephone practice, because of the dominant energy of the stronger or harsher vibrations, and the exclusion or smothering of the fainter sound waves. A clearly defined resonance is also noticeable when the horn or mouth-piece is directly attached to the body of the transmitter, imposing on the electrical voice currents not only the vibrations of the diapragm through the variable resistance of the carbon particles, but also the jar or resonant tone of the horn. There is also the objection of a too direct action upon the diaphragm of those sound waves reaching the diaphragm through the center of the horn, while those 'sound waves encountering the horn at an angle are impinged against the slanting sides of the horn, and are practically neutralized in force, thereby failing to transmit the fainter vibrations which are requisite to give'timbre to the reproduced articulations.

To overcome these and other objections, and to neutralize the attendant echo, I have discovered that a non-resonant receptacle of a general bell-shape, forgatherin and synchronizing the sound waves in ependently of electrical transmissiom combined with a diaphragm-provided sensitive transmitter but so related to such receptacle UNITED STATES PATENT OFFIC E.

DE ELBER'I A. REYNOLDS. OF WEEHA-WKEN. IN'EWY JERSEY, ASSIGNOR, BY MESNE AS- SIGNMENTS, TO AUDIPHONE COMPANY OF AMERICA, OF NEW YORK, N. Y., A COR- AUDIPHONE.

Serial No. 240,418.

whereby all vibrations other than those directly transmitted to the center of the dia- .phragm are excluded from efl'ective relarelative to the receptacle so that a greater or less volume of sound may reach the diaphragm, thus adapting it to all varying conditions of use.

A particular structural feature of the present invention com rises a bell-shaped sound collector embo ying non-vibratable material and provided with a conical pro jection at its central zone, a base provided with an opening, the walls of which form a sound passage with the walls of such conical projection and a microphone having its vibratable diaphragm exposed to sound waves transmitted through such sound passage. Such base is preferably mounted adjustably within the sound collector, to thereby adjust the effective direction and effective cross sectional area of such passage. Such microphone is preferably provided with a contact and means for regulating the pressure of such contact such pressure regulating means being supported by such base.

The invention as a whole is designed to be formed of individually separable parts constructed and arranged to be readily assembled, and to permit ready adjustment of the respective parts after assembly.

Further features and objects of my inven tion will be understood from the following description and accompanying drawings, in which- Fig. 1 is a sectional view" of my invention showing the transmitter and its relation to other parts of the apparatus; and

Fig. 2 is a front elevation of Figure 1.

In the drawings forming part of my specification, 1 represents a bell-shaped receptacle of non-resonant material, preferably made of aluminum with a coating of felt, or two aluminum receptacles 1, 1", with felt 1 between. 2 represents a bracket or support for the receptacle, 3 is a spider having the outer ends of the spider arms secured in any suitable manner to the receptacle 1. To the inner ends of the spider arms is attached the ferrule 4 and set-screw .5 for adjustably securing the rod 6.

The transmitter comprises preferably, a curved frame 7, having a central opening 7 a serving as the inlet opening of the transmitter, and 'further provided with means for supporting the diaphragm 8 of the transmitter. The transmitter further comprises the felt ring 9, enclosing the 'granib lar carbon 10, constituting the variable resistance in the transmitter circuit. The front electrode 11, or carbon button, is carried by the diaphragm 8, and is positioned at one end of the felt ring 9, whereas the other electrode 12, or carbon disc is positioned at the opposite end of the felt ring 9.

13 and 14 represent flexible rings or washers for the purpose of steadying the periphery of the diaphragm 8 without gripping it too tightly; 15 is an adjustable plate of slight resiliency, oval in form, with a slightly extended point 16 at the center engaging the carbon disc 12 and combining with means hereinafter set forth for exerting pressure u on the disc 12, and therewith on the fe t ring 9 and ultimately on the diaphragm 8, whereby the diaphragm 8 is given a slightly convex form upon which the sound waves impinge.

17 is a box-shaped container of suitable material, and constructed to-encase the diaphragm 8, felt ring 9, carbon disc 12,

Y granular carbon 11, and plate 15, in such a manner as to accord free workings of all the parts, and serving as a base for the adjustment screws 18, 19 and '20. Said container 17 is rovided with a central recess 21, within w ich the rod 6 is seated. The base 17 is preferably inserted in the frame 7 by screw threadin or by set screws 22 or equivalent adjusta le means for exerting any desired tension upon the flexible rings 13 and 14. The frame is preferably recessed at its periphery to receive the shield 23, of

non-resonant material, which is attached to the rod 6 bymeans of a set-screw 24.

Between the'spider 3 and the bell-sha ed receptacle 1, I prefer to insert felt was ers 25, and a felt ferrule 26 between the spider 3 and the rod 6, in order to preclude the transfer of any vibrations from the bellshaped receptacle 1 to the diaphragm 8.

The front electrode 11 is preferably attached to the diaphragm 8, by means of a small bolt 27, also serving as a terminal for the wire 28, leading to the binding post 29. The other terminal 30 may be attached to the plate 15, and the other lead wire 31 passed through an aperture 32 in the base 17 and the aperture 33 in the shield 23 and connected to the binding post 34.

cal projection 35.

carbon of the transmitter.

Preferably, my non-resonant receptacle is constructed to comprise the conical projecting portion 35 and the curved frame 7 with an inwardly flaring, circular opening 7, the longitudinal axis of which is in snip stantial alignment with the axis of the coni Also, the curved frame 7 is preferably provided with a compression chamber 36 communicating centrally with .the intake opening 7 and coacting with the diaphragm 8, to increase the sensibility of the transmitter.

While it is possible to use many forms of transmitter in my audiphone, I find that a transmitter especially desi ed for faint vibrations is far 'more satisfactory; the special form of transmitter set forth above as one preferred form of a part of my invention isadvantageous in that the pressure upon the diaphragm is centrally exerted by means'of the adjustable flexible plate and the yieldable felt ring, thereby giving the diaphragm a rounding-or oval form of an audiphone, such ring constituting, at the same time, a receptacle for the granular carbon. Such pressure means acts as a flexible damper means for the diaphragm, rendering the transmitter extremely sensitive to faint sound waves, and at the same time afl'ording more adjustability to meet varied requirements than is possible with prior art devices.

I have found that where two or more damper springs are employed upon a diaphragm, inore or less removed from its center, that an uneven tension obtains thereby impairing transmission, which disadvantages are magnified when a finer adjustment is attempted in the effort to correctl transmit the fainter sound waves, or vi rations emitted at some distance from the apparatus. This is entirely overcome by a substantially central pressure upon the diaphragm. My adjustment means enables the operator to re late the tension or damper upon the diap ragm to meet any condition that may arise, and is constructed to be adjustable, for any desired degree of sensibility, after the apparatus has been fully assembled.

My present invention is essentially an electrical audiphone, designed to collect distant sound waves or vibrations of the air, and through a variable resistance, transmit the same electrically. In connection with a multiplex induction coil, such as the one described in my pending application, Serial Number 203,382, entitled Induction coils, filed November 22, 1917, a number of electrical audiphones may be employed in one or several places, the vibrations or sound waves from which will be perfectly synchronized, while by the use of the invention of Egbert A. Reynolds and myself, as described in our pending application Serial Number 183,215, entitled Sound reproducing instrument, filed July 28, 1917 those sound waves are amplified to any desired extent, effectually reproducing in an audible manner, and without the aid of an ear-piece or other apparatus, the music, dialogue or other articulations from the rostrum of a theatre, a pulpit or the like, to any and all parts of the edifice, or to distant points.

\Vhereas I have described my invention by reference to specific forms thereof, it will be understood that many changes and modifications may be made Without departing from the principle of the invention.

I claim:

1. In an electrical device, a sound collector provided with an inner projecting portion, a transmitter disposed within said sound collector and means for adjustably mounting said transmitter relative to said projecting portion, said mounting means comprising a member in fixed relation to said sound collector, an element secured to said transmitter and adjustable means connecting said member and said element.

2, In an electrical device, a sound collector provided with an inner centrally disposed projecting portion, a transmitter disposed within said sound collector and means for adjustably positioning said transmitter, said positioning means comprising a member in fixed relation to said sound collector and provided with a recess, an element carrying said transmitter and projecting through said recess and adjustable means for holding said element in said recess.

3. In an electrical device, a sound collector provided with an inner centrally disposed conical projecting portion, a transmitter, a member comprising aplurality of arms, means for securing said arms respectively in fixed relation to said sound collector, said member being provided with a substantially central recess, an element carrying said transmitter and projecting through said recess and a set screw for securing said element in adjustable position in said recess.

In testimony whereof I have signed this specification this 4th day of June 1918.

DE ELBERT A. REYNOLDS. 

